Ruby Phenomenon : Rosser Reeves Ruby

The Rosser Reeves Ruby is a priceless gemstone due to its significance in the precious stone artifacts and its great rarity. Not only does it weigh over 138.7 carats but it is also a star stone. A star stone is a stone with a pattern of a 6 ray star that is visible in a cabochon cut and is also known as an asterism. This phenomenon is present only in fancy gemstones and is caused by impurities in the stone which are enhanced with its reflectiveness when a light is shined on the needle like inclusions. The stone, named after its previous owner, used to carry it around in his pocket for good luck. The original weight of the stone was 140 carats and although rubies have a hardness of a 9 on the Mohs scale, the stone had to be repolished due to deep scratches. You can see the Rosser Reeves Ruby on display at the Smithsonian National Museum of Natural History in Washington, DC.